Laser augmented diamond drilling apparatus and method

Abstract

A laser beam is transmitted through a drill bit comprising diamond or other suitable light-transmitting material having sufficient hardness. The laser beam exits a tip of the drill bit, thereby heating and softening the material being drilled at and/or near the interface of the drill with the material being drilled. The process may be utilized to drill hard and brittle materials such as ceramics and semiconductors, composites and ceramic matrix composites. The process may cause high pressure phase transformation, resulting in a more ductile and plastic material near the drill point/tip. The process provides more rapid drilling, improved surface quality in drilled holes, and less tool wear.

The invention claimed is: 
     
       1. A method of machining a hard and/or brittle material, the method comprising:
 directing a laser beam into at least a portion of a light-transmitting cutting tool comprising a solid light-transmitting material having at least one cutting edge formed by the solid light-transmitting material at an intersection of a rake face and a flank face whereby the laser beam enters the solid light-transmitting material, is transmitted through the solid light-transmitting material, and exits the solid light-transmitting material through at least one of the cutting edge, the rake face, and the flank face; 
 bringing the solid light-transmitting material of the cutting edge into moving contact with a surface of a hard and/or brittle material whereby the laser beam heats the surface and softens the material adjacent the surface. 
 
     
     
       2. The method of  claim 1 , wherein:
 the cutting tool has first and second opposite ends, and wherein the cutting edge is disposed on the first end, and the laser beam enters the second end of the cutting tool. 
 
     
     
       3. The method of  claim 1 , wherein:
 the light-transmitting material comprises a single crystal diamond. 
 
     
     
       4. The method of  claim 2 , wherein:
 the light-transmitting material comprises a poly crystal diamond. 
 
     
     
       5. The method of  claim 1 , wherein:
 the cutting tool comprises a drill bit having an elongated cutting edge; and wherein: 
 the laser beam has an oblong shape in cross section that is aligned with the elongated cutting edge. 
 
     
     
       6. The method of  claim 1 , wherein:
 the brittle material comprises a ceramic. 
 
     
     
       7. The method of  claim 1 , wherein:
 the brittle material comprises single crystal silicon. 
 
     
     
       8. The method of  claim 1 , including:
 introducing cutting fluid onto at least one of the surface of the brittle material and the cutting tool. 
 
     
     
       9. The method of  claim 1 , wherein:
 the cutting tool comprises a drill bit having at least two elongated cutting edges formed by a one-piece single crystal diamond material and wherein: 
 the laser beam exits the drill bit along the at least two cutting edges. 
 
     
     
       10. A laser-assisted machining system, comprising:
 a laser source; 
 a movable cutting tool having first and second opposite ends, the second end having at least one cutting edge, and wherein the cutting edge of the cutting tool comprises a substantially solid light-transmitting material; 
 wherein the laser source is configured to direct a laser beam from the laser source into the substantially solid light-transmitting material of the cutting tool whereby the laser beam is transmitted through the light-transmitting material and exits the substantially solid light-transmitting material at the second end of the cutting tool and heats a material being machined by the cutting edge of the movable cutting tool wherein the cutting tool comprises a drill bit having at least one cutting edge comprising a light-transmitting diamond material. 
 
     
     
       11. The laser-assisted machining system of  claim 10 , wherein:
 the drill bit includes two cutting edges comprising a light-transmitting diamond material. 
 
     
     
       12. The laser-assisted machining system of  claim 10 , including:
 an optical fiber operably interconnecting the laser source and the movable cutting tool. 
 
     
     
       13. The laser-assisted machining system of  claim 10 , wherein:
 the laser source comprises an IR CW laser. 
 
     
     
       14. A drill bit assembly comprising:
 a metal body portion having a passageway; 
 a drill bit comprising a solid light-transmitting material and having a light-receiving surface formed by the solid light-transmitting material and at least one elongated light-transmitting cutting edge formed by the solid light-transmitting material, wherein the light-receiving surface is in optical communication with the passageway such that a laser beam can be directed through the passageway into the light-receiving surface and through the solid light-transmitting material of the drill bit, whereby the laser beam exits the solid light-transmitting material at the at least one cutting edge. 
 
     
     
       15. The drill bit assembly of  claim 14 , wherein:
 the solid light-transmitting material of the drill bit comprises a single crystal diamond material. 
 
     
     
       16. The drill bit assembly of  claim 14 , wherein:
 the solid light-transmitting material of the drill bit comprises a poly crystal diamond material. 
 
     
     
       17. The drill bit assembly of  claim 14 , wherein:
 the solid light-transmitting material of the drill bit comprises two cutting edges. 
 
     
     
       18. The drill bit assembly of  claim 14 , wherein:
 the drill bit comprises a substantially transparent material.